So when a USB hub looses packets, it might go unnoticed for a mouse, but it creates real trouble for measure and control applications. Contrarily to Ethernet or WiFi networks, where packet loss are expected and taken into account, USB protocols are not designed to handle retransmissions. Those who don't loose packets, and have usually been a bit more expensiveĪ USB bus is not expected to loose packets: USB is supposed to provide a lossless transport layer.Those who loose packets, and happen to be mostly cheap ones purchased from retail outlet.From this test, we can immediately distinguish between two groups of USB hubs: This reproduces what would happen when you connect for instance several Yocto-3D-V2 inertial sensors, or a few analog interfaces like the Yocto-0-10V-Rx reading fast-changing signals. Our first test is designed to observe how various USB hubs react to a small number of devices configured to send data at high frequency. We will therefore test these two aspects separately. The first thing to know is that the maximum number of USB devices that you can use depends as much from the USB hubs as from the USB host controller.
#Dlink powered usb hubs safe for mac? full#
In this way, we will be able to run specific tests with devices creating USB trafic at 1Hz, 10Hz, 100Hz or even 1 KHz, which is the maximum message transfer rate allowed by the USB Full Speed standard used by Yoctopuce devices. Actually these are just Yocto-Demo with a custom firmware allowing to setup at will the number of measures reported per second. In order to get real numbers, we have built a batch of USB test devices, which behave like Yoctopuce sensors. At the same time, we will let you know what are the ideal conditions to maximize this limit. Our goal is to determine how many Yoctopuce USB devices, either sensors or actuators, you can hope to get working properly on a machine. To give you a better and more useful answer, we have decided to test what works in real life.
Unfortunately, life is not as simple: this naive reasoning does not take into account all constraints imposed by USB controllers. So before you pull out your wallet, make sure that the USB hub you plan to get suits your lifestyle.The USB specification plans for 127 device adresses on the USB bus, and it is tempting to deduce from this that you can connect up to 127 devices on a USB port. When choosing between the two, keep in mind that the best USB hub to buy is the one that best suits your specific needs. Meanwhile, non-powered ones are good for people who prioritize portability over function and speed.
Generally, powered USB hubs are ideal for people who need to connect multiple devices to their laptop’s USB ports on a daily basis. If you only transfer files occasionally, then this won’t be an issue, but if you constantly rotate files from one device to another, then it can definitely affect your work speed.īy using a powered USB hub, you can significantly speed up data transfers from a couple of minutes to a few seconds. You might notice a delay when transferring files from one drive to another. One issue with non-powered USB hubs is the slow data transfer.
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